Objectives: 1. Detailed correlation of changes in conformation of chymotrypsin derivatives measured by x-ray diffraction, chemical and physical studies (joint with Prof. Alexander Tulinsky, Michigan State University). 2. Resolution of the conformation, charge or chemical differences in alpha-chymotrypsin substates as a prototype study for substate transitions. Control of substates remaining with the monomethioninesulfoxide derivates of the chymotrypsins. 3. Resolution of the wide discrepancies reported for the thermodynamic changes in alpha-chymotrypsin on binding competitive inhibitors of the three main classes. 4. Studies of the source of metastability in alpha-chymotrypsin. 5. Hydrogen-exchange studies to characterize the "mobile-defect" systems of the chymotrypsins and their variation on inhibitor binding and chemical derivatization. 6. Steady-state rate studies of monomethioninesulfoxide-alpha-chymotrypsin to obtain enthalpy, entropy and free-energy changes along the reaction coordinate using chemically quite different members of the substrate series N-acetyl-L-aminoacid-ethylester. 7. Study of the ubiquitous linear relationship between enthalpy and entropy changes (compensation "law") previously attributed to water but now found to be a property of the "mobile-defect" system of the protein conformation. The protein is used as a probe for study of water, particularly at the protein-water interface.